1. Field of the Invention
This invention relates generally to an industrial truck having a stabilizing device to increase the stability of the truck.
2. Technical Considerations
When industrial lift trucks, and in particular counterbalanced fork lift trucks, are operated incorrectly or are used for purposes other than those for which they were designed, the vehicle may tip over sideways, in which case the driver could be seriously injured or even killed. Industrial trucks can also tip over forward, e.g., in the event of sudden braking when the load is raised. Finally, there are also critical operating conditions in which the rear axle, i.e., the steering axle, could lift up when the brakes are applied. Therefore, attempts have been made to increase the stability of industrial trucks and/or to emit alarm signals in the event of unsafe operating conditions.
For example EP 0 891 883 A1 describes a generic industrial truck in which the load status is monitored by means of various sensors, and in which the steering axle, which is in the form of a floating or swing axle on the rear end of the truck, is locked (hydraulic stop) in certain operating conditions to increase stability. The load status is monitored by a load height sensor which measures the height of the load-holding device, a load sensor which measures the hydraulic pressure of the lifting cylinder, a load inclination sensor which measures the inclination of the tilting cylinder and thus of the lifting mast, a steering angle sensor which measures the deflection or angle of the steered wheels, and a speed sensor. This construction is technically quite complex and may not achieve the desired effect of increasing stability under all operating conditions.
Therefore, it is an object of the invention to provide an industrial truck of the type described above that has a stabilizing device with a simple construction to increase stability and that makes it possible to stabilize the industrial truck under almost all operating conditions.